Air handling systems used to condition buildings or rooms typically include a unit designed to regulate, circulate, and condition air as part of the primary ventilation system of the buildings. These air handling systems often include a single intake, a mixing plenum, and two sets of ducts, each with its own set of fans, to convey the conditioned air to separate buildings or rooms. Although such a dual-discharge configuration may provide certain advantages over using two separate systems, such as efficiency and maintainability benefits, it also requires balancing the airflow discharged from the mixing plenum through the two ducts. Different configurations of the two ducts, greater restrictions in one duct relative to the other, and the like can lead to over-volume and/or under-volume conditions in the ducts. For example, balancing the discharge airflows to within a few thousand cubic feet per minute (CFM) of each other is required to maintain balanced temperature, balanced airflow over burners, and the like between the two ducts.
Conventional solutions include manually testing airflow and statically balancing the system, usually by introducing added restrictions to one of the ducts, but the system will become imbalanced as soon as the operating point and/or other parameters are changed during operation of the system. Continuing operation with the airflow imbalance leads to imbalances between the two ducts, such as imbalanced temperature, airflow over burners, and the like.